Power or manually released cargo latch

ABSTRACT

A cargo latch releasable either electrically or at remote or proximal points manually, comprising a lever having an arm movable across the mouth of the latch body. Control of the lever movement is effected by a series of sears and secondary levers arranged in a unique, compact and advantageous manner to give positive action, great strength and at the same time easy release.

United States Patent [72] Inventor Joseph R. Metz c/o Norco Inc., P.0. Box 405, Georgetown, Conn. 06829 [21] Appi. No. 887,816

[22] Filed Dec. 24, 1969 [45] Patented Dec. 28, 1971 [54] POWER OR MANUALLY RELEASED CARGO LATCH 10 Claims, 13 Drawing Figs.

[52] U.S. Cl 294/83 [51] lnt.Cl B66c1/34 [50] Field oi Search 294/83 R, 83 A, 83 AB, 88

[5 6] References Cited UNITED STATES PATENTS 2,858,161 10/1958 Smith 294/83 R Primary Examiner-Richard E. Aegerter Assistant Examiner-l. Kenneth Silverman Attorney-H. Gibner Lehmann ABSTRACT: A cargo latch releasable either electrically or at remote or proximal points manually, comprising a lever having an arm movable across the mouth of the latch body. Control of the lever movement is effected by a series of sears and secondary levers arranged in a unique, compact and advantageous manner to give positive action, great strength and at the same time easy release.

PATENTEI] 052281911 3.630.562

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INVENTOR R Mail gave/v7 POWER R MANUALLY RELEASED CARGO LATCH CROSS REFERENCES TO RELATED APPLICATIONS Copending application, of Joseph R. Metz, Ser. No. 800,475, filed Feb. 19, I969. entitled Power or Manually Released Cargo Latch," and having common ownership with the present application.

BACKGROUND This invention relates to power-operated cargo latches, also commonly referred to as cargo hooks, of the kind adapted to latch onto fittings such as metal bars or rings attached to the cargo. Latches of this type are used with helicopters, to pick up, transport and discharge cargo or other loads.

Heretofore, cargo latches of the kind referred to generally comprised a notched latch body which pivotally mounted a load beam or jaw adapted to swing across the notch mouth. The load beam was actuated by a system which included a solenoid and toggles and levers, the latter being precisely dimensioned and assembled to effect the desired result. The use of toggles required that tolerances be closely held, since dimensional variations could readily result in malfunction. Moreover, any appreciable wear would have a similar undesired result, this being due to the very nature of toggles of the kind involved with powerful loads. In consequence the necessary care in manufacture made for an increased cost, and the need for adequate lubrication and cleanliness in minimizing wear of the various parts also constituted a disadvantage.

SUMMARY The above drawbacks and disadvantages of prior cargo latches or hooks are obviated by the present invention, one object being the provision of an improved heavy duty poweroperated cargo latch which is not especially critical in the tolerances and manufacture, and not likely to malfunction readily as a consequence of ordinary wear. Another object of the invention is to provide an improved latch as above set forth, which is easily actuated while at the same time being strong and powerful. These objects are accomplished by the provision of a latch mechanism wherein a movable load member is controlled by a series of manually or solenoidpowered scars and secondary levers which can release the load member, the arrangement being such that an advantageous mechanical advantage is had while at the same time critical tolerances are eliminated.

Other features and advantages of the invention reside in an improved latch as above characterized, which is simple and relatively economical in construction, small and compact, easily maintained and serviced, resistant to vibration and other adverse environments, and not likely to jam or fail even when severely used.

Still other features and advantages will hereinafter appear.

IN THE DRAWINGS FIG. 1 is a front edge elevational view of the improved solenoid-powered cargo latch as provided by the invention.

FIG. 2 is a front edge elevational view of the latch.

FIG. 3 is a back edge elevational view of the latch.

FIG. 4 is a bottom plan view of the latch.

FIG. 5 is a fragmentary section taken on the line 55 of FIG. 1.

FIG. 6 is a view like that of FIG. 1 but with a sideplate removed to reveal interior details. The load lever is shown in the latching position in both these figures.

FIG. 7 is a fragmentary view of the assemblage of FIG. 6 but showing the latch released under load by energization of a solenoid operator thereof.

FIG. 8 is a fragmentary view like that of FIG. 7 but showing a no-load release of the latch, by a proximal manual means or operator.

FIG. 9 is a fragmentary view similar to that of FIG. 8 but showing a remote manual release.

FIG. 10 is a fragmentary side-elevational view of the latch showing the load lever in retracted or releasing position, and showing a latching bar assemblage in the reset or cocking position.

FIG. 11 is a view like FIG. 10 but showing a latched position, with the latch holding a load ring of %-inch-diameter cross section.

FIG. 12 is a view like FIGS. 10 and II but showing the latching bar assemblage in overtravel position.

FIG. 13 is a view like FIGS. 10, I1, and 12 but showing the latched position with the load lever holding a load ring of IQ- inch-diameter cross section.

Considering first FIGS. 1-4, the improved solenoidpowered cargo latch as shown therein comprises two casing halves 10, ll adapted to be secured together by screws to form a complete housing or latch body l2. At their upper portions, the casing halves 10, 11 have large aligned openings 13 receiving the pivot pin 16 of a universal-joint fitting I4 which is thereby pivotally secured to the latch body 12 and is secured to an anchorage plate 15 by a bolt 17.

The casing halves 10, 11 also have aligned deep bottom notches 20, 22 which together form the latch body throat or mouth 24, the latter being characterized by opposite parallel sides 26, 28. The mouth 24 is adapted to receive a fitting of a cargo load, such as a bar or load ring 30 indicated in broken outline in FIGS. 1,6 and 12, or a ring 31 indicated in FIG. 11. In these figures, the load bar or ring would be seen in transverse section.

In accordance with the present invention, there is movably carried by the latch body 12 a load-holding means comprising a hook-shaped load member or lever 32 and, related thereto, a control means comprising a series of hand or solenoid powered secondary levers or sears by which an advantageous control over the release of the load lever 32 is had, all to the end that the load ring 30 (or ring 31) may be either held captive in the mouth 24 as seen in FIGS. 1, 6, 11 and 13, or else released therefrom as indicated in FIGS. 7-10.

The load lever 32 (see FIG. 5) is roughly of rectangular section at its nose or bill portion 34, the tip of said portion being tapered when viewed from the side as in FIGS. 1, 6 and 8. The lever 32 has a slightly angular body portion 36, 37 which is accommodated substantially completely in a space 38 formed by the two casing halves 10, l l. A fulcrum shaft 40 rotatably supported by the casing halves I0, 11 is splined by a key 41 to the lever 32 to constitute a means for actuating the same from the casing exterior.

When in a blocking position extended across or disposed in the mouth 24, the bill portion 34 of the lever 32 holds captive the load ring 30 (or 31), whereas when the lever is swung to a retracted, releasing position (as seen in FIGS. 7 and 10) so as to withdraw the bill portion 34 from the mouth 24 of the latch body 12, the fitting or load ring is free for release from said mouth.

The upper arm 37 of the lever 32 is provided at its extremity with a pin 50 which engages and is cooperable with a first sear 52 (which may be considered essentially as a secondary lever) having a pivot 54 and a blocking face or shoulder 56 disposed closely adjacent the pivot 54. The blocking face 56 is engagea-' ble with the load-holding means which here comprises the pin 50 as seen in FIG. 6, thereby holding the load lever 32 in the holding or locking position shown therein. The angular position of the face 56 is such that a load on the lever 36 which tends to swing it counterclockwise will tend to swing the sear 52 clockwise about the pivot 54, thus making the fastening action more secure. The first sear 52 has a relatively long control arm 58 giving an appreciable mechanical advantage, said arm extending to a point remote from the pivot 54 and the extremity of the arm having a roller 60 which is engageable with a blocking face 62 of a second sear 64 carried on a pivot 66. As seen in FIG. 6, such engagement prevents the first sear 52 from swinging downward from its blocking position to the releasing position to release the lever arm 37; thus the lever 32 is maintained in the latching position. The sear 64 engages a bellcrank 65 carried on a pivot 69 and having an arm 70 which is engageable with the sear 52. This arrangement is involved with effecting the release of the latch. For if the second sear 64 should be swung slightly counterclockwise from the blocking position of FIG. 6 to the unblocking position shown in FIG. 7, the first sear 52 is unlocked and can then swing downward or counterclockwise; it is forced downward or counterclockwise by the bellcrank arm 70, since the bellcrank 65 is driven clockwise by the sear 64. This releases the pin 50 on the arm 37 of the load lever 32 whereby the latter can swing counterclockwise to the position shown in FIG. 7. This movement of the load lever 32 is effected by the force of a compression spring 67, and also by the force of the load carried by the load ring 30. Such ring exerts a counterclockwise force on the lever 32, thereby tending to shift the same from the position of FIG. 6 to the position of FIG. 7. The bellcrank 65 constitutes a means response to the unblocking actuation of the second sear 64, for shifting the first sear 52 to its releasing position, thus to free the load-holding means 32.

The second sear 64 has an angle-shaped actuator arm 68 which is engageable with the plunger 71 of a solenoid 72 mounted in the clasp body, said solenoid being supplied with current through lead wires 74. When the solenoid 72 is energized, the plunger 71 thereof is forced downward. As the plunger engages the sear actuator arm 68 it swings the second sear 64 counterclockwise to the FIG. 7 position, thereby effecting by means of the intermediate components a release of the load lever 32.

The first and second sears 52, 64 are biased respectively in clockwise directions by compression springs 76, 78 as seen in FIG. 6. If, as will be later brought out, the shaft 40 is shifted clockwise, considering FIG. 7, this and the action of the spring 67 will return the lever 32 to its locking position whereby the first and second sears 52, 64 will return to their latching positions under the actions of their respective springs, all as shown in FIG. 6.

The latching of advancing movement of the load lever 32 is effected by means of a latching bar assemblage 80 carried by the pivotal shaft 40 of the load lever 32, said assemblage including a crossbar 81 joined to two arms 82 secured at their ends to the shaft 40. For the releasing condition of the latch, the crossbar 81 of the latching arms 82 (see FIGS. 7, 8 and is disposed in a lower position across the inner end of the mouth 24. When the load ring (or ring 31) is inserted fully in the mouth, it will shift the crossbar 81 upward and the arms 82 clockwise as viewed in FIGS. 7 and 10, to the position of FIGS. 1 and 11, 12 or 13, thus effecting a clockwise movement of the load lever 32. The latching arms 82 are rigidly affixed to the pivot shaft which also has rigidly affixed to it the load lever 32 whereby these four components all move as a unit, as will be understood.

It will be noted that the latch construction as above set forth is devoid of toggle systems but instead involves only levers and scars. Accordingly, critical tolerances are not required, in contradistinction to load-carrying toggles, nor is there a likelihood of malfunctioning as components wear in ordinary usage. It is well known that powerful toggle systems (which do not employ resilient parts) must be accurately dimensioned in order to function satisfactorily.

In accordance with the present invention, a novel, semiprotected release mechanism is provided to enable reliable proximal manual release of the latch to be effected. As seen in FIGS. 6 and 8, the latch body 12 pivotally carries a release lever or member 84 in the form of a bellcrank, having an arm 86 engageable with the actuator arm 68 of the second sear 64. The bellcrank 84 has a second arm 88 projecting into a recess 90 of the latch body, there being a release ring or handle 92 connected to the arm 88 to actuate the bellcrank or release lever 84. Pulling on the handle 92 will swing the bellcrank 84 clockwise, thereby swinging the second sear 64 counterclockwise so as to effectuate the release of the load lever 32. Since the pull handle 92 is disposed within the recess 90 of the latch body it is in a large measure protected from damage and displacement whereby it provides a reliable proximal manual release means.

A remote manual release is also provided, in accordance with the invention, comprising a remote release cable 94 passing through a tubular guide 96 carried in the latch body 12. The inner end of the cable 94 is connected to a fitting 98 on a bellcrank arm 100, said bellcrank being acted on by a spring 101 and being pivoted at 102. The bellcrank has a second arm 104 carrying a roller 106 which is engageable with the second sear 64 in such a manner that when the bellcrank 100 is pivoted clockwise, as by pulling on the release cable 94, the roller 106 will shift the second sear 64 counterclockwise so as to release the first sear 52. Return of the release cable 94 to the latching position shown in FIG. 6 will enable the sears to reset themselves when entry of the load ring 30 occurs and shifts the load lever 32 clockwise. The releasing action as effected by the remote control cable 94 is illustrated in FIG. 9.

An important feature of the invention resides in the provision of the external latching bar assemblage which is readily accessible. If for some reason difficulty is had in overcoming the force of the spring 67 by the load ring and latching bar 81 for the purpose of effecting the latching movement of the load lever 32, such lever may be positively shifted to the latching position by applying suitable force to the latch arms 82.

FIG. 10 shows the load lever 32 retracted, it being normally held in this position under the action of the spring 67. The latching bar 81 and latching anns 82 are extended in readiness for engagement by the load ring (30 or 31) attached to the cargo. FIG. 11 depicts the insertion of the small-section ring 31, which has lifted the latching bar 81 and arms 82. Completion of the latching movement of the bar 81 and lever 32 may be effected by external force applied to the arms 82, whereupon the sears 52 and 64 take over the maintenance of the latching. FIG. 12 shows the insertion of the large-section load ring 30, which has fully lifted the latching bar 81 and latching arms 82 in overtravel position and has fully shifted the load lever 32 to its latching position, secured by the sears 52, 64. FIG. 13 shows the latched condition when the load is being carried, after the overtravel position of FIG. 12 has occurred.

It will now be understood from the foregoing that I have provided a novel and improved cargo latch involving powerreleased load lever which is controlled by a series of secondary levers and sears, as distinguished from toggle links and the like. With the present improved construction, highly critical tolerances need not be maintained, and slight changes in dimensions due to ordinary wear will not result in malfunctioning of the latch. Relatively few parts are involved, these being of simple construction, and the entire latch may be readily fabricated and quickly economically assembled.

Variations and modifications are possible, and portions of the improvement may be used without others.

lclaim:

1. A cargo latch comprising, in combination:

a. a latch body having a mouth to receive a fitting of a cargo load,

b. load holding means including a load member movably carried by the latch body and movable either into said mouth to a blocking position to block and hold the cargo fitting captive or else out of said mouth to a releasing position to release the fitting,

c. control means including a first sear, for restraining the load member in said blocking position in the body mouth,

d. said first sear comprising a lever having a blocking face engageable with said load-holding means and constituting part of said control means, said face being located closely adjacent the pivot of the first sear,

e. said first sear being movable between positions blocking and releasing said load-holding means and having a control arm extending to a point remote from said pivot,

f. a second sear comprising a lever having one arm engageable with the extremity of the said control arm when the second sear is in a blocking position, thereby to block the arm, said second sear being movable to an unblocking position wherein it is disengageable from said extremity to free said arm.

g. means for actuating the second sear to the unblocking position to effect release of the first scar, and

h. means responsive to said unblocking actuation of the second sear, for forcibly shifting said first sear to its releasing position, thereby to free the load-holding means whereby the load member can move out of the mouth of the latch body.

2. The invention as defined in claim ll, wherein:

a. said load member comprises a lever,

b. said load-holding means comprising an arm of said lever,

having its end engageable with the first sear.

3. The invention as defined in claim 1, wherein:

a. said means for actuating the second sear comprises a release member including a pull handle,

b. said latch body having a recess adjoining the mouth thereof, in which the pull handle is disposed to protect it from damage.

4. The invention as defined in claim 2, wherein:

a. said means for actuating the second sear comprises a bellcrank mounted on the latch body and a pull handle attached to the bellcrank.

5. The invention as defined in claim 1, wherein:

a. said means for actuating the second sear comprises a solenoid carried by the latch body, and an arm connected with the second sear and engageable with the plunger of the solenoid.

. The invention as defined in claim 1, wherein:

a. said means for actuating the second sear comprises a release lever engageable therewith and a remote control cable connected with the release lever and leading from the latch body.

. The invention as defined in claim 1 and further including:

spring means biasing said first and second sears to their blocking positions.

. The invention as defined in claim 1 and further including:

a latching bar pivotally carried by the latch body and extendable across the mouth thereof to be engaged and displaced by the cargo load fitting as the latter enters said mouth, and

b. means for effecting movement of the load member into the mouth in response to displacement of the latching bar.

. A cargo latch comprising, in combination:

a. a latch body having a mouth to receive a fitting of a cargo load,

b. load-holding means including a load member movably' carried by the latch body and movable either into said mouth to a blocking position to block and hold the cargo fitting captive or else out of said mouth to a releasing position to release the fitting.

0. control means including a first sear, for restraining the load member in said blocking position in the body mouth,

d. said first sear comprising a lever having a blocking face engageable with said load-holding means and constituting part of said control means, said face being located closely adjacent the pivot of the first sear,

e. said first sear being movable between positions blocking and releasing said load-holding means and having a control arm extending to a point remote from said pivot,

f. a second sear comprising a lever having one arm engageable with the extremity of the said control arm when the second sear is in a blocking position, thereby to block the arm, said second sear being movable to an unblocking position wherein it is disengageable from said extremity to free said arm,

g. means for actuating the second sear to the unblocking position to effect release of the first sear, and

h. means responsive to said unblocking actuation of the second sear, for shifting said first sear to its releasing position, thereby to free the load-holding means whereby the load member can move out of the mouth of the latch body,

i. a latching bar pivotally carried by the latch body and extendable across the mouth thereof to be engaged and displaced by the cargo load fitting as the latter enters said mouth,

j. means for effecting movement of the load member into the mouth in response to displacement of the latching bar,

k. said load member comprising a lever and a shaft fixedly carrying the lever, said shaft being turnable in the latch body,

I. said means for effecting movement of the load member comprising a reset arm affixed to said shaft 10. The invention as defined in claim 9, wherein:

a. the reset arm is disposed externally of the latch body so as to be accessible for manual operation. 

1. A cargo latch comprising, in combination: a. a latch body having a mouth to receive a fitting of a cargo load, b. load holding means including a load member movably carried by the latch body and movable either into said mouth to a blocking position to block and hold the cargo fitting captive or else out of said mouth to a releasing position to release the fitting, c. control means including a first sear, for restraining the load member in said blocking position in the body mouth, d. said first sear comprising a lever having a blocking face engageable with said load-holding means and constituting part of said control means, said face being located closely adjacent the pivot of the first sear, e. said first sear being movable between positions blocking and releasing said load-holding means and having a control arm extending to a point remote from said pivot, f. a second sear comprising a lever having one arm engageable with the extremity of the said control arm when the second sear is in a blocking position, thereby to block the arm, said second sear being movable to an unblocking position wherein it is disengageable from said extremity to free said arm. g. means for actuating the second sear to the unblocking position to effect release of the first sear, and h. means responsive to said unblocking actuation of the second sear, for forcibly shifting said first sear to its releasing position, thereby to free the load-holding means whereby the load member can move out of the mouth of the latch body.
 2. The invention as defined in claim 1, wherein: a. said load member comprises a lever, b. said load-holding means comprising an arm of said lever, having its end engageable with the first sear.
 3. The invention as defined in claim 1, wherein: a. said means for actuating the second sear comprises a release member including a pull handle, b. said latch body having a recess adjoining the mouth thereof, in which the pull handle is disposed to protect it from damage.
 4. The invention as defined in claim 2, wherein: a. said means for actuating the second sear comprises a bellcrank mounted on the latch body and a pull handle attached to the bellcrank.
 5. The invention as defined in claim 1, wherein: a. said means for actuating the second sear comprises a solenoid carried by the latch body, and an arm connected with the second sear and engageable with the plunger of the solenoid.
 6. The invention as defined in claim 1, wherein: a. said means for actuating the second sear comprises a release lever engageable therewith and a remote control cable connected with the release lever and leading from the latch body.
 7. The invention as defined in claim 1 and further including: a. spring means biasing said first and second sears to their blocking positions.
 8. The invention as defined in claim 1 and further including: a. a latching bar pivotally carried by the latch body and extendable across the mouth thereof to be engaged and displaced by the cargo load fitting as the latter enters said mouth, and b. means for effecting movement of the load member into the mouth in response to displacement of the latching bar.
 9. A cargo latch comprising, in combination: a. a latch body having a mouth to receive a fitting of a cargo load, b. load-holding means including a load member movably carried by the latch body and movable either into said mouth to a blocking position to block and hold the cargo fitting captive or else out of said mouth to a releasing position to release the fitting. c. control means including a first sear, for restraining the load member in said blocking position in the body mouth, d. said first sear comprising a lever having a blocking face engageable with said load-holding means and constituting part of said control means, said face being located closely adjacent the pivot of the first sear, e. said first sear being movable between positions blocking and releasing said load-holding means and having a control arm extending to a point remote from said pivot, f. a second sear comprising a lever having one arm engageable with the extremity of the said control arm when the second sear is in a blocking position, thereby to block the arm, said second sear being movable to an unblocking position wherein it is disengageable from said extremity to free said arm, g. means for actuating the second sear to the unblocking position to effect release of the first sear, and h. means responsive to said unblocking actuation of the second sear, for shifting said first sear to its releasing position, thereby to free the load-holding means whereby the load member can move out of the mouth of the latch body, i. a latching bar pivotally carried by the latch body and extendable across the mouth thereof to be engaged and displaced by the cargo load fitting as the latter enters said mouth, j. means for effecting movement of the load member into the mouth in response to displacement of the latching bar, k. said load member comprising a lever and a shaft fixedly carrying the lever, said shaft being turnable in the latch body, l. said means for effecting movement of the load member comprising a reset arm affixed to said shaft
 10. The invention as defined in claim 9, wherein: a. the reset arm is disposed externally of the latch body so as to be accessible for manual operation. 